Comparative Anatomy, Physiology, and Biochemistry of Mammalian Skin
David W. Hobson in Dermal and Ocular Toxicology, 2020
Elastic fibers are found in tissues that are capable of expansion. Elastic fibers consist of two protein components; elastin which is the main component and an amorphous substance, and a microfibrillar protein which acts as a mold for the elastin. Elastin is synthesized in fibroblasts similarly to collagen. Microfibrils are first formed by the fibroblasts and act as a mold for the newly formed elastin which then become a fiber. Ultrastructurally, elastic fibers do not exhibit a periodicity like collagen fibers. Elastic fibers stained for electron microscopy appear as an amorphous mass, with a few discrete microfibrils appearing at the periphery. This mass is usually light staining, while the microfibrils are more electron dense.38,199,202,204,206
Immunohistochemistry of the Pulmonary Extracellular Matrix
Joan Gil in Models of Lung Disease, 2020
Two of the best-characterized components of this group are elastin and fibronectin. Elastic fibers (Figs. 6b, 8a) are composed of an “amorphous” central core surrounded by a system of microfibrils (Cleary and Gibson, 1983; Damiano et al., 1979; Gosline and Rosenbloom, 1984). The central core contains elastin, a highly insoluble protein rich in desmosine and isodesmosine (Gosline and Rosenbloom, 1984); the composition of the peripheral microfibrils is not totally elucidated, but they are known to contain fibrilin (Sakai et al., 1986). The exact function of the peripheral microfibrils is not clear; however, they may serve to integrate elastin with the surrounding ECM (Cleary and Gibson, 1983). Unlike most ECM components, elastic fibers are well defined by conventional microscopy. In the lung, elastic fibers are found in blood vessels, airways, alveolar interstitium, and pleura (Cleary and Gibson, 1983; Damiano et al., 1979; Amenta et al., 1988). Elastin, a true elastomere, provides the recoil properties of elastic fibers (Cleary and Gibson, 1983; Gosline and Rosenbloom, 1984).
Hormonal Effects on Fascia in Women
David Lesondak, Angeli Maun Akey in Fascia, Function, and Medical Applications, 2020
Fascia, at the microscopic level, has hormonal receptors that can affect the body’s mechanical properties on a macroscopic level.28 In pregnancy and at the end of the follicular phase of the menstrual cycle, the sex steroid hormones progesterone and estrogen induce components of the extracellular matrix (ECM), namely expression of collagen, elastin, and fibrillin 1.29,30 Collagen is responsible for the stiffness of connective tissue while elastin and fibrillin are responsible for its stretchiness.3 Both elastin and fibrillin are elastic fiber components.30 Fibroblasts secrete the glycoprotein fibrillin, which increases fascial elasticity.31 Recall the clinical consequences of tissue collagen weakness as seen in Ehlers-Danlos syndrome, which results from defects in the genetic coding of collagen synthesis,31 and the hypermobility seen in Marfan syndrome, which results from a genetic mutation in the fibrillin-1 gene causing defects in fibrillin-1 synthesis.32
Severe elastolysis in hereditary gelsolin (AGel) amyloidosis
Published in Amyloid, 2020
Susanna Koskelainen, Fang Zhao, Hannu Kalimo, Marc Baumann, Sari Kiuru-Enari
Tissue elasticity is based on elastic fibres, which are insoluble components of the connective tissue, for example in skin and blood vessels. Elastic fibres are assembled during mid-gestation and designed to maintain their function for a lifetime [24]. Elastic fibres are formed of an amorphous, crosslinked elastin core and a surrounding fibrillin-rich microfibrillar mantle [24]. Elastin is the most abundant protein in mature elastic fibres, comprising approximately 90% of the structure [25]. It is extremely stable and relatively resistant to proteinases, including aggressive proteolytic enzymes known as elastases [26]. Therefore, the degradation of mature elastin normally progresses very slowly, over years or decades. Elastolysis is assumed to be the result of a disturbance in the normal balance between proteinases and their inhibitors [27]. It is observed, for example, in vessel walls during ageing and atherosclerosis [28].
Cell homing strategy as a promising approach to the vitality of pulp-dentin complexes in endodontic therapy: focus on potential biomaterials
Published in Expert Opinion on Biological Therapy, 2022
Elaheh Dalir Abdolahinia, Zahra Safari, Sayed Soroush Sadat Kachouei, Ramin Zabeti Jahromi, Nastaran Atashkar, Amirreza Karbalaeihasanesfahani, Mahdieh Alipour, Nastaran Hashemzadeh, Simin Sharifi, Solmaz Maleki Dizaj
The dental pulp is made up of loosely linked collagen and elastin fibers in the mouth [138]. The matrix’s toughness and tensile strength are provided by unbundled, randomly dispersed type I and III collagen fibers that are more thickly distributed around blood vessels and nerves. Elastic fibers and collagen fibers have a high degree of elasticity [139]. A collagen I-collagen III-elastic polymer composite scaffold may aid in the regeneration of dental pulp tissue. Poly (1, 8octanediol-co-citrate) (POC) is an example of a soft scaffold that may recover after deformation. Cell culture and subcutaneous implantation studies confirmed the cells’ and tissues’ compatibility in vitro and in vivo. POC, which has been used to regenerate blood arteries, tendons, and ligaments, may be utilized to repair dental pulp.
Histological and ultrastructural evaluation of human decellularized matrix as a hernia repair device
Published in Ultrastructural Pathology, 2018
Martina Ghetti, Valentina Papa, Giovanni Deluca, Valeria Purpura, Paolo Ruscelli, Davide Melandri, Daniela Capirossi, Evandro Nigrisoli, Paola Minghetti, Elena Bondioli, Giovanna Cenacchi
The HDM pre-transplant was characterized by a dense, acellular, haphazardly structured collagen matrix (Figure1 A and B), without blood vessels. Using the Weigert staining, numerous randomly disposed elastic fibers were identified (Figure 1 C), which appeared disrupted, probably due to the decellularization process. After one year, the HDM biopsies were obtained, and the specimens showed numerous fibroblasts present on the matrix as well as an extensive neoangiogenesis (Figure 1 D in the middle). The graft presented a highly oriented collagen pattern as in a normal dermal tissue (Figure 1 E). In addition, the elastic fibers were thin and parallel to collagen fibers (Figure 1 F). Hypertrophic fibroblasts were present in a small area where the collagen matrix was still remodeling, that was interpreted as a sign of tissue regeneration (Figure 2 A). Only a few inflammatory cells were present at the periphery of the HDM biopsy specimens. Only in patient 2, a typical foreign-body tissue response was present, including few multinucleated giant cells around blood vessels (Figure 2 B). A histological comparison of HDMs pre-transplant (taken from three different tissue donors) was also performed in order to compare the matrix differences before transplant (Figure 3 A, B, C). All the HDMs pre-transplant were well decellularized, but the HDM of donor 2 appeared to be less dense compared to the others two (Figure 3 B).